LED with Amber

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Recently when using some LED fixtures with the ORB XF, I had problems with the desk not having any concept of the amber channel. Whilst it could be changed by going into the fixture manually, it was unaffected by the colour picker. This made it very difficult to achieve desired colours and then desired brightness for whites.

What's the best way to use this desk with lights that support more than just RGB?

I'm going to be working with some of the ETC LED fixtures in the near future, which I understand have 7 different groups of LED's (Indigo, Lime, Amber, Cyan, Red, Blue, Green). The lights have an RGB mode, but (and I quote from the manual)

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A recent software update now allows the colour picker to use white too to create better pastille colours. Amber is currently not included in this. I wonder whether the Source Four LED Lustr allows for RGBW control of all 7 chips? If so this would give fairly accurate control.

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The Colour Picker will only affect the RGB values. Amber can then be added in / removed using the dedicated encoder wheel. I'd ensure that Amber is defaulted to 0% rather than 100% (if this isn't already the case, this can be altered in SETUP > Edit Fixtures > Defaults)

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The Colour Picker will only affect the RGB values. Amber can then be added in / removed using the dedicated encoder wheel.

Hi Jon,

I knew that a few other consoles on the market (different manufacturer) are able to "translate" RGB values from the picker (or those related to a color from LEE, Rosco, etc) to RGBA, RGBW, RGBAW or even ETC's color mixing with seven different LED emitters.

We now support RGBW fixtures within the colour picker and filter lookups. To do this, we make a very crude assumption that "white" LEDs are always the same (that being "all frequencies"). This is clearly not true, and therefor it's up to the Lighting Designer to choose a fixture with "white" LEDs that they like / are most suitable for the performance. That being said, we've had great feedback on our implementation, not just from users but from multiple fixture manufactures too.

Amber (or any other colour) becomes a little more difficult because there's no definition of what "Amber" (or any other colour) is, or exactly where it lies within the frequencies / hues.

Trying to solve this, some organisations take real life measurements of each fixture type and use these to try to calibrate control consoles. However, we believe there are multiple reasons why this doesn't give us a full solution:

For the calibration to work efficiently, you need 100% of the fixtures in your rig to have had their measurements taken. No one has (or can) take measurements of every fixture type that's released into the market place, and therefor the likelihood you'll have a rig made up of 100% measured fixtures is minimal.

Even once a fixture type has been measured, there are too many external variables. Try getting the same colour (and intensity) out of two discharge lamps, when one is brand new and the other is towards the end of it's life. Even if the lamps are replaced at the same time, the measurements are only accurate at the point your fixture has the same lamp hours as the fixture that was measured.

LEDs can change over time too, and even more frustratingly between batches. Therefor, two identical fixtures, both used for the same number of hours, can show a difference in colour. Especially at the lower end of the market.

Even if you solve all of the above, we're assuming you're projecting onto a white surface. As soon as the surface changes colour, the operator is required to counteract this colour shift anyway (if they can).

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That's a really interesting paper Jon. It's from 2014, do you know where the standard got to and what industry adoption is like?

I've not heard much talk of this so maybe not much? It looks to me that a lot of the complexity could be in the fixture rather than the controller, so maybe not attractive to manufacturers except for high end fixtures?

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thanks for your answer. My impression is, you're approaching a very perfect solution. I really like people seeking for the perfect solution...

But maybe you're making things too difficult for yourself:

RGBA/RGBAW only applies for LED fixtures, doesn't it? All discharge lamps are combined with subtractive colour mixing (CMY).

Supporting RGB fixtures you currently have the same problems: What frequency does the red/green/blue LED emitter have? How long are they in use? Are there any differences in colour between the different fixture types or batches from the same fixture?

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In theory that would be best, however as the paper stated, fixture manufacturers vary from much more orangey-red ambers, to actually more like yellows, and therefore this could ruin the colour the console tries to create, rather than add to it.

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fixture manufacturers vary from much more orangey-red ambers, to actually more like yellows

I'm sorry, I hadn't the time to read through it, so I had just taken a short look into the paper.

What you'd like to say is that the differences with amber are bigger than those with red, green and blue?

It would be very interesting how other console manufactures solved the problem, because there are a few with support for amber (or even more colours) in the picker. One more question on my list for the PLS fair in Frankfurt

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Why not have a calobration feature where each individual fixture can be calobrated by the user within the edit fixture screen. With my Led fixtures they already have calobration that i can set what colour temperature my fixturs output at allowing me to match them all to look the same.

I agree that there could be at the very least an approximation for each fixture. With many of these fixtures, certainly those at the cheaper end of the spectrum, I am not expecting 100% colour reproduction. Similarly, I wouldn't mind if the picker wasn't 100% accurate either. I mean, it's not like we're plugging IPS panels into the desk, calibrating them and installing colour profiles or using optimal lighting conditions for the monitors use. The accuracy of the picker was realistically lost some time ago. The crucial aspect is what it physically looks like on stage.

What I think would be nice is either for a 'best guess' calibration per fixture as part of the library. Obviously this is a huge amount of work for someone at Eaton, but it doesn't have to cover every fixture, just those most commonly used, or those that are particularly problematic. It could also be done over time. You could also then provide customers that are super 'colour-conscious' with the ability to input individual fixture calibrations, perhaps with some sort of USB based calibration hardware attached to the desk that runs through the parameters of the fixture and makes adjustments to the fixture based on its readings.

You could have the first fixture library with fixture colour calibration with support for any number of control channels or coloured LED's. Then come out with a fixture colour calibration tool for colour sensitive applications.

Just an idea, it would be interesting to know your thoughts!

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Thanks OllieB for your post! I'd like to add another tought to it: Why don't let the users do the calibration for the fixtures they use, and provide a simple possibility to give it back to the community, improving the library? This way Zero88's staff a) do not have to calibrate every fixture, even those that are never or seldom used have a lower workload.